Curti/ages of the nose.—Of these, one com pletes the septum, and the rest form the skele ton of the lower and lateral portion of the exter nal nose.
The cartilage of the septum (septum mobile nasi) (fig. 400) is the only one immediately connected with the bones. It occupies, in ge neral, nearly the middle vertical plane of the nose ; but, like the osseous septum, it often deviates to one or the other side, and has sur faces more or less curved. Its outline varies with the general shape of the nose, but is usually bounded by three unequally curved lines, of which the infetior is the longest, and the anterior and. superior are of about equal length. Its superior border (a, fig. 400) is fixed in the.whole length of the groove which usually exists in the lower margin of the per pendicular plate of the ethmoid bone : it is directed very obliquely backwards and down wards, and at its posterior extremity is conti Fig. 400.
nued with a curve into the lower border (b), of which a part fits in the same manner in the anterior margin of the vomer, while the remain der projects straightforwards in front of the anterior nasal spine, and forms the base and middle part of the columna (sous-cloison,) or partition between the apertures of the nostrils. ' Anteriorly, this lower border of the cartila ginous septum is continued with a curve which' lies at the apex of the nose, into the anterior border (c). This last lies immediately be neath the skin, and, becoming gradually thick er, is continued upwards to the junction of the nasal bones, where the cartilage (at d) is thicker than at any other part.
Of the lateral cartilages, two on each side are regularly found. The upper pair, (a, fig.
. . . ' ' 4c)1,) wmcn are named superior, Laurin, or triangular cartilages, have each in general the form of a triangle with its angles rounded off. In front they are continuous, or very closely connected wiwth the upper half of the anterior edge of the cartilage of the septum ;• but each of them projects a little beyond it, so that it lies in a kind of groove between them; and, sometimes, each is prolonged downwards in a free sharp process by its side. Behind, they are closely attached by fibro-cellular tissue to the rough part of the free margins of the nasal and superior maxillary bone,s. Below, theii
margins are connected with the autilar,es be. neath them (b, fig. 401) by a tough at thin and pliant fibrous membrane, in which several small oval portions of cartilage are sometime, arranged in a row.
The inferior cartilages ( fig. 402, and b, ,fig 401) are also called puma/ cartilages, or card lag,es the alit, because they form the basic e the tnore freely moveable lateral parts of nose, and the cartilages of the nostrils, be cause they surround and in great measure de termine the form of those apertures. The chief portion of each of them is nearly elliptical, and occupies the anterior part of the ala of the nose. Posteriorly, this portion either becomes suddenly narrower, and is continued in a long, undulating, and curved process through the middle part of the ala to the posterior and outer boundary of the nostril ; or else it ab ruptly ceases, and, in place of the process, there is a row of three or more small oval portions of cartilage, (sesamoid cartilages,) imbedded in the fibrous membrane vvhich forms the rest of the basis of the ala, and connects all the moveable cartilag,es to one another. Anteriorly, this chief elliptical por tion is also continued into a narrow process, which, after proceeding for a very short dis tance forwards, turns round abruptly, and is directed backwards and a little downwards by the side of the lower margin of the cartilaginous septum, to which, as well as to its fellow on the opposite side, it is pretty closely connected by fibro-cellular tissue. In this course, the carti lage reaches a little beyond the anterior edge of the septum, so that, at the tip of most noses, there is in the middle line a small fossa bounded on each side by the lateral cartilages, and at the bottom of which is the anterior edge of the septum. The inner portion of this cartilage extends along about two-thirds of the inner boundary of the nostril, and terminates in an evenly rounded border ; its lower margin is always rather lower than that of the cartilagi nous septum, and assists in giving width and support to the columna. Sometimes, but more rarely, this inner process of the inferior cartilage is, like the posterior and outer process, separate froin the chief elliptical portion.